Drawbridge.



CLAUDE A.

Il?,` TURNER, OF MINNEAPOLIS, MINNESOTA.

DRAWBRIDGE.

Speeilieaton ot' Letters Patent.

Patented Aue'. et, 1914.

Application filed December 27, 1913. Serial No. 808,939.

To all who/m, it may concern i Be it known that I, @nanna A. l). TURNER,ot' Minneapolis, in the county of Hennepin, and in the State ofMinnesota, have in vented' a certain new and useful improvement inDrawbridges, and` do hereby de! claro that the following is a fall,clear, and exact. description thereof My invention relates to drawbridges of the type shown in United States Patent No. 503,273, issuedAugust 13, 1893, to l?. A. lil/*arnet* and myself, and the object of myinvention is to improve the mechanism o't' that patent for raising thetoggle joint for lifting the ends of the arms of the draw spanpreliminary to opening, or swinging the bridge. In that patent the apexof the toggle is connected by a transverse pin to the lower end of avertically movable screw by the revolution of which the toggle joint israised or lowered and there are certain objections to the constructionwhich is the object more particularlyof my present invention to obviate.

My invention, therefore, relates particularly to the mechanism forimparting the desired vertical movement to the toggle joint.

lin the accompanying drawings- Figure 1 is a top plan view in the natureof a diagram showing a draw bridge of the type of that of the patentabove mentioned; Fig. 2. is a side elevation thereof the full linesshowing' the bridge in its `closed position and the dotted lines showingthe posi tion of the parts when the toggle joint has been raised to liftthe bridge `arms 'trom their bearings on the abutments; l*l 3 is adetail View in vertical section of the toggle joint lifting mechanism;Fig'. 4 is an end elevation thereof with parts in section; Fig. 5 is atop plan view thereof. I

ln its general construction, as may be seen by reference to Figs. 1 and2,; the drawbridge shown corresponds to that of said Patent No. 503,273,that is to say, .the bridge is mounted upon a central t'urny table 10which supports the two oppositely extending arms 11., said arms havingat tiroir inner ends struts 12 which at their point of connection withthe top chords of the arms at their upper ends are connected tothe outerends of the toggles 13, the inner eiids ot' the toggles being broughttogether anld lapped past each other and connected byl a transverse pinlet, the holes in the toggle eyes being horizontally elongated to allowfor the necessary play upon the pin due to the vertical movement oi" thetoggle joint.

The toggle pin 14; rests in a semi-circular bearing in the top of asaddle 15, which at cach side of the pin has a horizontal extension 16with an internally threaded hole through which passes a vertical screw17, the two screws being, respectively, right and lett handed andsuitable bearing being provided in the trame work 18. Upon each of thescrews 1T is keyed, or otherwise secured, a gear 1S) and between the twogears 19 and meshing with both of them is a pinion 20 upon a verticaloperating' shaft 21 by the revolution of which, either by hand or bypower, the screws are simultaneously revolved in opposite directions andthe saddle thereby caused to move vertically and the togajgle jointthereby raised when the direction of the revolution of the screws issuch as to move the saddle and the toggle pin 14: thereon upward. ltwill be seen that by the employment of the two screws there is notorsional or twisting effect whatever upon the pin 1-14 which resultsfrom the single screw and nut arrangement of the construction of thepatent before mentioned, and hence, tendency of the latter to bind inthe guides S32 between which the pin at its opposite ends project, isavoided, so that the toggle pin 11i moves upward smoothly and freelywithout any bindingl tendency from sidewise or lateral movement; and itwill be seen that in other respects my present toggle joint lit'tn.:mochanif-nn is desirable in that it. is simple, its members being of thesimplest hind, and it is easily operated and powerful.

Having thus described my invention what l claim is- 1. As animjn'ovement in end lifts of center bearing draw bridges, thecombination ot a toggle, a toggle pin at the joint, a pair ot rotaryscrews at opposite sides of the tognle pin, connections between thescrews and the togg e pin, and means for revolving said screws.

9.. As an improvement in end lifts of centcr bearing draw bridges, thecombination ot' a oggi@ a toggle pin at the joint, a pair oi rotaryscrews at opposite sides of the toggle pin, connections between thescrews and the toggle pin, and means for revolving said screws, thescrews having, respectively, right and left thread.

As an improvement in end lifts of screw passing through each opening,said screws having right and left thread, gears on the respectivescrews, and a driving pinion between `the two gears meshing with 15 bothof them.

In testimony that I Claim the foregoing I have hereunto set my hand.

CLAUDE A. P. TURNER. litnessesz HENRY I. CHURCH, B. NV. ADAMS.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. C."

